1991 Pontiac Grand Prix Problems
RepairPal has identified the most common problems with the 1991 Pontiac Grand Prix based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.
The anti-lock brake (ABS) accumulator may fail causing loss of power brake assist. (The brake pedal will become very hard.)
The intake manifold gasket may develop and external engine oil or coolant leak. In some cases, an internal coolant leak may occur causing coolant to mix with the engine oil. Our technicians tell us that operating the engine with a coolant/oil mix can result in internal engine damage. Replacing the intake manifold gasket should correct these leaks.
The high pressure power steering hose will commonly leak fluid; it should be replaced.
The upper intake manifold gasket and/or a PCV vacuum lines/hoses can develop vacuum leaks with age. This type of leak can result in a higher that normal or rough idle.
The spark plugs should be replaced every 30,000 miles and the spark plug boots should be checked for hot spots and cracks.
An engine oil leak may develop from the oil pump drive O-ring. This can often be confused with an intake manifold gasket leak. Careful inspection is required to determine the exact cause of the leak. Replacement of the failed 0-ring will commonly correct this concern.